Attachment 94078 Details for Bug 72785 – Patch to test

Patch to test

0001-R600-Don-t-unconditionally-unroll-loops-with-private.patch (text/plain), 1.48 KB, created by Tom Stellard on 2014-02-14 16:18:50 UTC

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Creator: Tom Stellard

Created: 2014-02-14 16:18:50 UTC

Size: 1.48 KB

patch

obsolete

>From b817f9842a7c56a40d417c20e4dab5691cfec98b Mon Sep 17 00:00:00 2001
>From: Tom Stellard <thomas.stellard@amd.com>
>Date: Fri, 14 Feb 2014 10:46:06 -0500
>Subject: [PATCH] R600: Don't unconditionally unroll loops with private memory
> accesses
>
>This causes the size of the scrypt kernel to explode and eats all the
>memory on some systems.
>---
> lib/Target/R600/AMDGPUTargetTransformInfo.cpp | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
>diff --git a/lib/Target/R600/AMDGPUTargetTransformInfo.cpp b/lib/Target/R600/AMDGPUTargetTransformInfo.cpp
>index 7f37658..9cdfec5 100644
>--- a/lib/Target/R600/AMDGPUTargetTransformInfo.cpp
>+++ b/lib/Target/R600/AMDGPUTargetTransformInfo.cpp
>@@ -110,9 +110,13 @@ void AMDGPUTTI::getUnrollingPreferences(Loop *L,
>         // instructions that make it through to the code generator.  allocas
>         // require us to use indirect addressing, which is slow and prone to
>         // compiler bugs.  If this loop does an address calculation on an
>-        // alloca ptr, then we want to unconditionally unroll the loop.  In most
>-        // cases, this will make it possible for SROA to eliminate these allocas.
>-        UP.Threshold = UINT_MAX;
>+        // alloca ptr, then we want to use a higher than normal loop unroll
>+	// threshold.  This will give SROA a better chance to eliminate these
>+	// allocas.
>+	//
>+	// Don't use the maximum allowed value here as it will make some
>+	// programs way too big.
>+        UP.Threshold = 500;
>       }
>     }
>   }
>-- 
>1.8.1.5
>

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